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Capacity Fade Model (Application ID: 12667) unknown Parameters and equations

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Hello dear COMSOL community,

I am working right now on my master thesis and want to simulate some lithium-ion batteries. I downloaded your application (see subject) for capacity fading. Since i have some questions, I looked up for some support about the terms but didnt find them in the application desctiption. To the questions:

  • There are a bunch of paramters given within the project. Where do they come from? Like the density of the SEI-Layer or the aging parameters. Any references?

  • In the materials of the project there are some equations by the electrolyte. Here an example for the diffusion coefficient: DL_int1(c/1[mol/m^3])exp(16500/8.314(1/(T_ref/1[K])-1/(T2/1[K])))

where do these equasions come from? Are these the Arrhenius-Equations? When it is the Arrhenius-Equation, where are the calculations of the activating energy?

The same exponential equation is in neraly all parameters of the electrolyte but different values. It would be very helpful, if you could provide me with some references or any explanation.

I hope someone can help me

Best Regards Benjamin Schramm


2 Replies Last Post 14 nov 2017, 08:25 GMT-5
Henrik Ekström COMSOL Employee

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Posted: 7 years ago 14 nov 2017, 08:06 GMT-5

Literature references are included as Comments entries in the Batteries & Fuel Cells Materials database. These can be viewed using the Properties window of the Model Builder after a material has been added to the model.

Literature references are included as Comments entries in the Batteries & Fuel Cells Materials database. These can be viewed using the Properties window of the Model Builder after a material has been added to the model.

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Posted: 7 years ago 14 nov 2017, 08:25 GMT-5

Thank you for the quick reply. For me it is not clear, where the eq. "" comes from and how is the 16500 calculated? I've read the papers added to the electrolyte EC:EMC (3:7) and I would guess it comes from the Maxwell-Stefan Diffusion. But then the question is, why is the same eq. in the conductivity and activationcoefficient? Here the eq. from these to:

activationcoefficient: What does -1000 stand for?

conductivity: What does 4000 stand for?

Firthermore is an explanation of the interpolations needed.

It is very confusion, where the data comes from. I would appreciate it if there will be any help.

Thank you for the quick reply. For me it is not clear, where the eq. "(c/1[mol/m^3]) * exp(16500/8.314 * (1/(Tref/1[K])-1/(T2/1[K])))" comes from and how is the 16500 calculated? I've read the papers added to the electrolyte EC:EMC (3:7) and I would guess it comes from the Maxwell-Stefan Diffusion. But then the question is, why is the same eq. in the conductivity and activationcoefficient? Here the eq. from these to: activationcoefficient: (c/1[mol/m^3]) * exp(-1000/8.314 * (1/(T_ref3/1[K])-1/(T4/1[K]))) What does -1000 stand for? conductivity: (c/1[mol/m^3])*exp(4000/8.314*(1/(T_ref2/1[K])-1/(T3/1[K]))) What does 4000 stand for? Firthermore is an explanation of the interpolations needed. It is very confusion, where the data comes from. I would appreciate it if there will be any help.

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